// Copyright (c) 2018, Yubico AB
// All rights reserved.
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package com.yubico.webauthn.attestation.resolver;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import com.yubico.webauthn.attestation.TrustResolver;
import java.security.cert.X509Certificate;
import java.util.Collection;
import java.util.List;
import java.util.Optional;

/**
 * Resolves a metadata object whose associated certificate has signed the argument certificate, or
 * is equal to the argument certificate.
 */
public class SimpleTrustResolverWithEquality implements TrustResolver {

  private final SimpleTrustResolver subresolver;
  private final Multimap<String, X509Certificate> trustedCerts = ArrayListMultimap.create();

  public SimpleTrustResolverWithEquality(Collection<X509Certificate> trustedCertificates) {
    subresolver = new SimpleTrustResolver(trustedCertificates);

    for (X509Certificate cert : trustedCertificates) {
      trustedCerts.put(cert.getSubjectDN().getName(), cert);
    }
  }

  @Override
  public Optional<X509Certificate> resolveTrustAnchor(
      X509Certificate attestationCertificate, List<X509Certificate> caCertificateChain) {
    Optional<X509Certificate> subResult =
        subresolver.resolveTrustAnchor(attestationCertificate, caCertificateChain);

    if (subResult.isPresent()) {
      return subResult;
    } else {
      for (X509Certificate cert :
          trustedCerts.get(attestationCertificate.getSubjectDN().getName())) {
        if (cert.equals(attestationCertificate)) {
          return Optional.of(cert);
        }
      }

      return Optional.empty();
    }
  }
}
